Printing is a process that involves the production of black and white or color documents on a variety of substrates, predominantly paper. These documents may consist of single or multiple pages. The pages may be conventional (without bleed) or pages with bleed. Bleed is defined as xe2x80x9cany image that goes directly to the edge of paper, seeming to run off (bleed) from the sheetxe2x80x9d (See xe2x80x9cGetting it Printedxe2x80x9d by Mark Beach, North Light Books, Cincinnati, 1993, Page 107).
Most documents today are designed using popular page layout programs, such as QuarkXpress or FreeHand, running on Macintosh or PC computers. These application programs are sometimes called Desktop Publishing (DTP) programs. Use of these programs results in a document in digital format such as PostScript(copyright), (For more information on PostScript see the xe2x80x9cPostScript(copyright) Language Reference Manualxe2x80x9d, Adobe Systems Inc., Addison-Wesley Inc., February 1990), Portable Document Format (PDF), as defined by Adobe Systems, Inc., in their Nov. 7, 1996, Version 1.2 Document, or other format that is sent to the printer on magnetic or other storage media or via various means of communication. Most DTP page layout programs simulate an onscreen page of a defined size placed on a drawing table. This is called a xe2x80x9cpagexe2x80x9d and the drawing table is called a xe2x80x9cpasteboardxe2x80x9d, The document originator can place graphic elements and text on both the xe2x80x9cpagexe2x80x9d and the xe2x80x9cpasteboardxe2x80x9d, but only the information placed on the area defined as a page will be printed. Elements which overflow from the page to the pasteboard will be cut to the page""s limit during separation film or plate preparation, or during the digital printing process.
When a page with bleed is included in a document, the bleed size can be explicitly defined by a DTP application, when placing the elements on the pasteboard, overflowing from the page area. Publication designers commonly consider the entire production process, including finishing, and indicate the pages to be printed with bleed. This is done by providing files with proper embedded bleed information. Sometimes, a hard copy record accompanies the job printing instructions to assist the printer.
When the document is printed by a traditional printing method such as offset gravure or flexography, printing a page with bleed does not present a problem. The image is printed on paper larger than the final page size, and the paper is later trimmed mechanically. The traditional printing process, which includes the prepress stages of film and plate preparation, is a very forgiving one, and bleed may be introduced even if the designer has initially omitted the information. This is done by using manual and electronic prepress tools and methods through which the information to be printed on the page will be retained or added. A hard proof that normally accompanies the traditional printing process is also of help in finalizing job composition and bleed generation.
The emerging digital printing process is different from the traditional one in a number of major aspects. Pages are printed on precut paper, and in many cases, standard size paper is used. Additionally, there is no xe2x80x9cprepressxe2x80x9d stage between the document origination stage (design) and the printing stage, and no hard copy proof accompanies the job.
As a result, when a document to be printed contains pages with bleed, an automated digital workflow cannot be implemented. The pages with embedded bleed are defined as pages of a larger size than other pages in the same document. To enable the printing of a document containing pages with and without bleed by digital printing methods, the pages with bleed must be identified prior to printing, extracted from the document, printed on a larger sheet of paper that will be trimmed later and manually introduced into a collated document. If such a page identification operation, which is interactive, is not performed, the entire document will be printed on larger paper, and it will then be necessary to trim it in the course of the finishing process. Such a printing method causes additional paper waste and increases the cost of printing.
If the bleed specification was not introduced by the designer during the design stage, but the information needed for bleed generation is present, the printer will have to generate the bleed using interactive prepress tools. In a more extreme case, where the bleed information has been omitted altogether, the page will have to be modified.
In all of these cases, interactive intervention is required by the operator. As the operator""s intervention in the process is currently the only way to print pages with bleed in a digital manner, it does not enable the automation of the digital printing process. Also, it adversely affects the key benefits of digital printing; mainly, its ability to maintain a completely automated workflow and print in the electronic collation mode, where the pages are printed in the order that they appear in a complete document.
Among others, the above drawback impedes faster transition from conventional to digital printing methods because of the lack of capability to support a fully automated digital printing workflow. It is the purpose of the present invention to offer a method and apparatus that enables an automated digital printing workflow, including recognition and generation of pages with bleed as well as a method to print them digitally.
Accordingly, it is a primary object of the present invention to provide a method of automated digital printing of complete documents containing multiple pages. The document may include both pages without bleed and pages with bleed. The pages may be printed by an apparatus that operates on the basis of electrostatic printing, thermal printing, ink jet printing or any other digital printing technique on paper or on any other media, the selection of which may be included in the document.
It is another object of this invention to provide a method of digitally printing pages with bleed, where the pages to be printed are supplied in digital form and the bleed information for printing is generated automatically.
It is still another object of this invention to provide a method of automatically, digitally printing documents containing both images on pages with and without bleed, where the pages with bleed are printed on oversized paper and pages without bleed are printed on regular paper, precut to size.
It is a further object of this invention to provide a method of digitally printing pages with bleed of a document where the pages to be printed are supplied in digital form and where the bleed information for printing is generated automatically, comprising the steps of determining and selecting whether the pages should be of a selected, single size; identifying pages with generated bleed marking, when pages of a single size have been selected; calculating image size on pages with bleed; and printing all pages of the same document on a selected printing medium.
It is a still further object of this invention to provide a method of digitally printing pages with bleed of a document, where the pages to be printed are supplied in digital form and where the bleed information for printing is generated automatically, comprising the steps of determining and selecting whether pages should be of a single size; identifying and separating pages with generated bleed marking, when pages of more than one size have been selected; printing pages without bleed on one size of precut printing medium; and printing pages with bleed on printing medium larger than said one size of precut medium.
Another object of this invention is to provide a method of automatically, digitally printing documents containing both images on pages with and without bleed, where both, the pages with bleed and the pages without bleed, are printed on regular paper, precut to size, and where the pages with bleed and without bleed are electronically collated into one document.
Still another object of this invention is to provide a method of digitally printing pages with bleed of a document, where the images to be printed are supplied in digital form and where the information for printing is generated automatically, comprising the steps of identifying and marking pages with bleed, calculating image size on pages with bleed, determining whether the pages should be printed on a single sized printing medium, and printing all pages of the same document on a selected printing medium when a single sized medium is selected.
A further object of this invention is to provide a digital printing apparatus system for printing pages, some of which have bleed, where the images to be printed are supplied in digital form and where the bleed information for printing is generated automatically comprising, a digital front end having an input, a digital printing engine having at least two print medium sizes on line, said digital front end having interface means for connection with said printing engine for driving it, input source means for connection to the input of said digital front end for providing information in digital form to said digital front end for control of said digital printing engine for pages with and without bleed on appropriate size print medium.
These and other advantages, features and objects will become more apparent from the following description taken in connection with the illustrations in the accompanying drawings.